The kind folks over at WSUS off-line (thanks aker) have created a free off-line updating tool for WHSv1.

Last time I checked, Microsoft is only pushing 2-3 dozen updates for this OS thru on-line updating. This off-line update tool contains all 236 w2k3r2 updates, all the WHSv1 power packs and update rollups, and all the wanna cry updates. It's only pre-requisite is that you have pre-installed a OEM version of WHSv1 or a HP mediasmart server OS system disk. While it has not been tested, it should also work with other OE branded WHSv1 OS disks (Acer EasyStor, etc.).

Installs are seamless, basically you load the tool onto the desktop, click auto restart, and walk away. After four or 5 auto restarts, the OS is fully up to date.

The tool can be downloaded from the WSUS off line forum site from the link on page 5 of the Missing Updates/WHS thread or directly using the below link.